1. Field of the Invention
The present invention relates to a rotor of a generator or motor, and more particularly, to a magnetic rotor of a generator or motor.
Further, the present invention relates to a rotor of a generator having an auxiliary coil provided around a rotor body.
2. Background of the Related Art
Generally, a generator is a device that generates an electromotive force by electromagnetic induction to convert a mechanical energy into an electrical energy. Most of generators are rotators, and recently, linearly moving generators are developed.
The generator requires magnets producing a magnetic field and a conductor generating an electromotive force, and in this case, any one of the magnets and the conductor should be moved. A generator in which the conductor stops and the magnetic field rotates is a revolving field type, and contrarily, a generator in which the conductor rotates and the magnetic field stops is a revolving armature type.
Permanent magnets are used in a small-sized generator, but generally, an electromagnet, that is formed by winding coils around a core to apply direct current to the coils, is adopted for generators. In this case, if the current is increased or decreased, the strength of the electromagnet can also be increased or decreased, such that the magnitude of the electromotive force can be freely varied.
On the other hand, according to the prior art as disclosed in Korean Patent No. 373427 entitled ‘magnetic motor and generator’, a plurality of slits are radially formed around an iron core, and a plurality of magnets are detachably inserted into the corresponding slits, such that the magnetic flux in an air gap between a stator and a rotor can be increased or decreased.
In the prior art where the permanent magnets are inserted to the rotor, however, the lines of magnetic force caused by the permanent magnets may be formed differently from that upon the initial designing, in the rotor conducting a rotary movement at a high speed, thereby making it difficult to adjust the variables that give influence on the magnetic flux.
Since the magnetic flux and the lines of magnetic force are varied in the arrangement of the plurality of permanent magnets, further, the experiments or studies on the their arrangement should be executed continuously.
On the other hand, there occurs a problem that the rotor and stator of the generator are overheated by the electromagnetic induction.
In a case where a rotor shaft is formed of a conductive metal, furthermore, there occurs a problem that the electricity induced to the rotor is conductive to the rotor shaft.
On the other hand, the generator includes a cylindrical stator and a rotor having a rotary shaft in such a manner as to be rotatably inserted into the hollow of the stator. Further, the stator has coils wound to slots at the inside thereof and the rotor has permanent magnets coupled thereon. In some cases, of course, the stator has the permanent magnets coupled thereon and the rotor has the coils wound therearound.
The generator is a device that forcedly rotates the rotor to generate an electromotive force by the electromagnetic induction between the permanent magnets of the rotor and the coils of the stator and thus supplies the generated electromotive force as an output voltage to load.
In the generator supplying the output voltage to the load, there is a need for the continuous supply of a predetermined size of voltage to the load, which enhances a quality of electricity. In the conventional generators, however, the waveforms of the output voltage may be distorted by the generation of over shoot caused upon the initial load supply or upon the drastic variations of the load size, thereby making the quality of electricity deteriorated.
Additionally, the size of the output voltage of the generator is adjusted by the rotation speed of the rotor, but in the conventional generator it is difficult to control the rotation speed of the rotor in a precise manner, such that there is a problem that the fine adjustment of the output voltage is not accomplished. Since the size of the load is larger than one expected, moreover, only the magnetic force of the permanent magnets does not generate sufficiently the output voltage.
Also, the sectional areas of the permanent magnets around the outer periphery of the rotor body have a generally square shape. In a case of the rotor using the square-shaped permanent magnets, as shown in FIG. 12, the distribution of magnetic flux (the lines of magnetic force) is not uniform in the rotor body and the magnetic flux is lost in the rotor body, thereby reducing the generation efficiency of the generator.
The rotor includes a connection member having a bearing and a fixing bracket formed on one end of the rotor shaft, for coupling the rotor and the stator. As the rotor and the stator are coupled by means of the connection member, the magnetic flux of the rotor is leaked to the stator through the rotor shaft and the connection member, and thus, circulating magnetic flux flows between the rotor and the stator.
Such the generation of the leaking magnetic flux and circulating magnetic flux makes the generation efficiency of the generator deteriorated and further causes the bearing of the connection member to be early abraded. At this state, if the leaking and circulating magnetic flux is left as it is, the electrical loss may be caused undesirably.